Book/Report

FZJ-2019-00542

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Halbleiterdetektor für ein mikrodosimetrisches Personendosimeter zur Anwendung in gemischten Neutronen-Gamma-Strahlenfeldern : Vergleich möglicher Prototypen

Schröder, O. (Corresponding author)FZJ*

1995
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/21315

Report No.: Juel-3054

Abstract: For the application in radiation protection dosirnetry the personal dose equivalent,Hp(10), in a depth of 10 mm in human tissue, has to be measured. Thus a detector of a personal dosemeter tobe used in mixed neutron gainrna radiation fields will be covered by 10 mm of tissue equivalent (TE) material. The energy and angular distribution of the secondary charged particle which are created in the TE layer will be similar to that originating from human tissue. The evaluation of human and biological data has shown that radiation effects are not only correlated to the energy deposited but fiepend also on the type and the energy distribution of the primary radiation. The quality factor, Q, was introduced to compensate for this effect. The pulse height distribution of the specific energy distribution of the secondaries allows not only for the calculation of the deposited dose, D, but also for the evaluation of the quality factor of the radiation. The concept of such a detector can be reali7ed with commercial semiconductor chips of different functionality. A single reverse biased pn junction of a large diode represents a simple analogous detector. The electron hole pairs originating form the slowing down of secondary charged particles are sampled. The amplified signal will be proportional to the deposited dose. A static random access memory (SRAM) Chip represents a better approach, as each memory cell (one bit) contain a radiation sensitive volume, which is located at the revere biased pn junction of one of its closed transistors. The stored information in a dynamic random access mernory (DRAM) chip can be neutralized by the created eharge, which allows for a threshold counter. In the scope of this work two silicon SRAM Chips of 4 kBit and 64 kBit storage capacity, one silicon 1 MBit DRAM chip and two galliumarsenide Schottky diodes of different lateral dimensions have been tested in various radiation fields. Monoenergetic alpha radiation has been used to identify the radiation sensitive volumes of each device. With the help of energy degradation methods the linearity of the detected signal had been verified. A collimated neutron bearn (<E$_{n}$> = 5.3 MeV) generated in a thick beryllium target by 14 MeV deuterons had been used for the main pari of the experiments. A comparison of the results with Chose of a tissue equivalent proportional counter which had been obtained from experiments in the saure neutron field manifest that semiconductor chips of different functionality could be used for the measurement of deposited dose and radiation quality. All semiconductor designs showed a relatively high noise level, which did not allow for a quantitative examination of the gamma component of the neutron radiation fields. The increasing need for personal neutron radiation protection devices due to the new recommendations of the International Commission for Radiological Protection (ICRP) give rise to the demand for further research work in this area. The development of an applicable personal neutron dosemeter based on a semiconductor detector Chip within five to ten years seeins to be possible, as the semiconductor technology provides smaller chips of even better functionality.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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